package org.zhadoop.stream.cql.semanticanalyzer.parser.context;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.zhadoop.stream.cql.exception.SemanticAnalyzerException;
import org.zhadoop.stream.cql.semanticanalyzer.analyzecontext.expressiondesc.ExpressionDescribe;
import org.zhadoop.stream.cql.semanticanalyzer.parsecontextreplacer.ParseContextReplacer;
import org.zhadoop.stream.cql.semanticanalyzer.parsecontextwalker.ParseContextWalker;

/**
 * exists表达式解析内容
 * @author zwd
 *
 */
public class ExpressionExistsContext extends BaseExpressionParseContext{

	private static final Logger LOG = LoggerFactory.getLogger(ExpressionPreviousContext.class);
	
	private SubQueryExpressionContext subquery;
	
	public SubQueryExpressionContext getSubquery() {
		return subquery;
	}

	public void setSubquery(SubQueryExpressionContext subquery) {
		this.subquery = subquery;
	}

	@Override
	public void walkChildAndReplace(ParseContextReplacer replacer) {
		// TODO Auto-generated method stub
		
	}

	@Override
	protected ExpressionDescribe createExpressionDesc() throws SemanticAnalyzerException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String toString() {
		return " EXISTS ( " + subquery.toString() + " ) ";
	}

	@Override
	protected void walkChild(ParseContextWalker walker) {
		// TODO Auto-generated method stub
		
	}

}
